/Engine/Source/Runtime/Engine/Classes/Materials/MaterialExpressionStrata.h
class UMaterialExpressionStrataWeight : public [UMaterialExpressionStrataBSDF](API\Runtime\Engine\Materials\UMaterialExpressionStrataBSDF)
FExpressionInpu...
A
Substrate material
FExpressionInpu...
Weight
Weight to apply to the Substrate material BSDFs